August 21, 2008 10:43AM

Dear Leo

Leo Casey, an award‐​winning teacher and a rep for the United Federation of Teachers, wrote a blog post today lamenting what he sees as cherry picking of studies by school choice advocates. Entirely apart from the validity of that claim, it bespeaks a desire on Mr. Casey’s part to look at the broadest possible array of relevant evidence. Good for him. I agree so strongly with his sentiment that I spent the last several months putting together the most comprehensive worldwide review of the evidence on public vs. private school outcomes to date, to be released in a few weeks (“Markets vs. Monopolies in Education: A Global Review of the Evidence”). It collects and tabulates 115 statistical findings drawn from 55 separate studies conducted in over 20 nations.

Most of these findings favor private provision of education over government provision. But, of course, private schools differ quite a bit in levels of regulation and sources of funding from one nation to another. To address that complication, I included a tabulation that specifically compares the most market‐​like private school systems (minimal regulation and at least some parent funding) with typical monopoly government school systems. The results of this more meaningful breakdown of the evidence differ noticeably from the vague public vs. private comparison. I’ll wait to mention just how they differ until the study’s official release in early September.

When the study is released, I hope that Mr. Casey will have a look at it, and share his thoughts on its findings. While it is possible that I have missed a few studies here and there, it will be difficult to make the argument that I have cherry picked the studies to favor private schooling, since I include all the studies mentioned by Mr. Casey in his post.